Attorney General Michael B. Mukasey issued new restrictions yesterday on contacts between Justice Department and White House officials regarding ongoing criminal or civil investigations, implementing his first major policy revision since taking office on Nov. 9.

Mukasey had promised to institute new guidelines in the wake of the U.S. attorney firings scandal, in which lawmakers and some prosecutors alleged that White House political aides and other officials were inappropriately informed about details of criminal or civil probes.

The new guidelines would restrict such communication but would still allow discussions between officials at all levels of the department and the White House about legislation, budgets, policy issues and political appointments, presumably including decisions to hire or fire U.S. attorneys.

In a memo yesterday to senior Justice Department officials and U.S. attorneys, Mukasey said that, "on many subjects, the White House and the Department must be able to communicate freely." But communication about pending criminal or civil cases "must be limited," Mukasey wrote. "The Department will advise the White House . . . only where it is important for the performance of the President's duties and where appropriate from a law enforcement perspective."

Mukasey said that contacts about pending criminal cases will be limited to the attorney general and his deputy and to the White House counsel and deputy counsel. Civil-enforcement investigations will be limited to the same officials, plus the associate attorney general, the department's third-in-command. Discussion of national security investigations will not be subject to limitations but will require notification of the attorney general or his two senior aides.

Sen. Sheldon Whitehouse (D-R.I.), a former U.S. attorney who sponsored legislation to establish restrictions on contacts between Justice Department officials and presidential aides, said in a statement yesterday that Mukasey's new rules will "restore safeguards against political interference at the Department of Justice."

Whitehouse estimated that, during the Clinton administration, no more than seven people at the White House and the Justice Department were authorized to initiate discussions about pending cases. That number ballooned to 40 under Attorney General John D. Ashcroft, and then to more than 900 throughout the executive branch under Ashcroft's successor, Alberto R. Gonzales, Whitehouse said.

Mukasey's move comes amid a rocky honeymoon period for the new attorney general, who angered lawmakers from both parties last week by refusing to share details about a preliminary inquiry into the CIA's destruction of videotapes. At a speech to the American Bar Association yesterday, Mukasey declined to comment on the ongoing investigation. He urged Congress to approve a new wiretapping bill, a matter that has been delayed until at least January.